I’ve seen a lot of posts of preschool graduations and kindergarten graduations. I’m curious, why do both still happen?

As kindergarten has become more like first grade of the past, are kids really graduating to anything after their first year of school in kindergarten? Is it a celebration of making it through the first year?

I see how preschool graduation came to be as most kids are actually moving on to a whole new school and now new classroom model. Seems to me like preschool graduation would replace kindergarten graduation. Yet, I imagine cases can be made for and against both. Curious what your thoughts are…